From: Omar Sandoval osandov@fb.com
[ Upstream commit 6d3113a193e3385c72240096fe397618ecab6e43 ]
In btrfs_submit_direct_hook(), if a direct I/O write doesn't span a RAID stripe or chunk, we submit orig_bio without cloning it. In this case, we don't increment pending_bios. Then, if btrfs_submit_dio_bio() fails, we decrement pending_bios to -1, and we never complete orig_bio. Fix it by initializing pending_bios to 1 instead of incrementing later.
Fixing this exposes another bug: we put orig_bio prematurely and then put it again from end_io. Fix it by not putting orig_bio.
After this change, pending_bios is really more of a reference count, but I'll leave that cleanup separate to keep the fix small.
Fixes: e65e15355429 ("btrfs: fix panic caused by direct IO") CC: stable@vger.kernel.org # 4.4+ Reviewed-by: Nikolay Borisov nborisov@suse.com Reviewed-by: Josef Bacik josef@toxicpanda.com Reviewed-by: Johannes Thumshirn johannes.thumshirn@wdc.com Signed-off-by: Omar Sandoval osandov@fb.com Signed-off-by: David Sterba dsterba@suse.com Signed-off-by: Sasha Levin sashal@kernel.org --- fs/btrfs/inode.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index 548e9cd1a337..972475eeb2dd 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -8294,7 +8294,6 @@ static int btrfs_submit_direct_hook(int rw, struct btrfs_dio_private *dip, bio->bi_private = dip; bio->bi_end_io = btrfs_end_dio_bio; btrfs_io_bio(bio)->logical = file_offset; - atomic_inc(&dip->pending_bios);
while (bvec <= (orig_bio->bi_io_vec + orig_bio->bi_vcnt - 1)) { if (map_length < submit_len + bvec->bv_len || @@ -8351,7 +8350,8 @@ static int btrfs_submit_direct_hook(int rw, struct btrfs_dio_private *dip, if (!ret) return 0;
- bio_put(bio); + if (bio != orig_bio) + bio_put(bio); out_err: dip->errors = 1; /* @@ -8398,7 +8398,7 @@ static void btrfs_submit_direct(int rw, struct bio *dio_bio, io_bio->bi_private = dip; dip->orig_bio = io_bio; dip->dio_bio = dio_bio; - atomic_set(&dip->pending_bios, 0); + atomic_set(&dip->pending_bios, 1); btrfs_bio = btrfs_io_bio(io_bio); btrfs_bio->logical = file_offset;